In the past decades many developments have taken place in the field of microfluidic systems. Important application fields are biochemical analysis and environmental measurements. With a certain application, production volume and complexity of the system concerned in mind, there is a choice of approaches for design and production. In case of smaller production volumes and bigger complexity a construction from separate standard components can be chosen, that are connected by means of metal, glass or plastic tubes, hoses and electric wires. The production may be labour-intensive and the dead volumes of the system will be rather large, but in a number of cases this may be the best approach, both economically and technically. For large production volumes it can be economically interesting to develop a made-to-measure solution. This made-to-measure solution consists preferably of a monolithic system and an integrated and automated production process. With the right design the internal dead volumes can be small. The development cost will be relatively high but the system and the production process can be fully optimised for this particular application.
For a medium sized production volume and a relatively complex system, one can choose for a hybrid solution, in which standard components are put together according to a purpose-designed, more or less generally usable process to make up the desired system. In this case one has the advantages of the use of standard components and a known process that can be used with minimal or no adaptations. A number of proposals has been made for such a hybrid solution, e.g. U.S. Pat. No. 5,640,995 and US 2004/0087043 and WO 2004/022233. The proposed processes however are not very generic, and besides that they generally cannot be sufficiently automated so the production remains relatively labour-intensive. Furthermore the precision required for mounting the components often can only be achieved with difficulty, if at all. Typical problems are leakage, obstruction of the channels by glue and the like, corrosion of the materials used by the applied liquids and contamination of the applied liquids and gases by the materials used.
In the building of a hybrid microfluidic system fluidic, electrical and mechanical connections must be made. The production requirements and functional requirements for these connections often are hard to reconcile. Known solutions are therefore characterised by compromises in the design and the choice of materials and processes. Ideally one would want to optimise each type of connection individually and be free to choose materials and processes. U.S. Pat. No. 6,540,961 describes a flow cell for (molecular biological) analysis and diagnostics comprising a first supporting substrate 102 (flex circuitry/PCB/semiconductive material) with fluidic and electr(on)ic components and a second substrate/flipped chip 112, which are mechanically connected by means of a sealant 130, and electrically connected by means of electrically conductive bumps 128. The sealant provides both a mechanical connection and a seal. Because both functions are not separated an independent optimisation of the fluidic connection and the mechanical connection is not possible. In EP 1415710 embodiments are described of a device for biochemical analysis, comprising one or more (DNA, RNA, protein) arrays. Among others, an integrated (microfluidic array) device 310 composed of one or more array components 312 and one or more microfluidic components 314 which are mutually connected mechanically and fluidically, but not electrically. An array component comprises one or more (flexible) array substrates 332 [0066]. An array component can be mechanically connected with a microfluidic component by means of clamps, clips or brackets and the like or by means of an adhesive, ultrasonic welding, etc. whereas the seal can be achieved by means of a gasket or sealant material [0071]. However no electrical connection is made in this way. A microfluidic component can comprise electrical features such as an electronics component/integrated circuit 512 [0091], in which the electronic component and the microfluidic component are mutually connected by means of a flip chip connection. [0094], but here no fluidic connection is made. The electronics component can also be mounted on top of a microfluidic feature such as a channel or chamber [102] but it is not indicated how a seal is made. In none of the mentioned documents making a mechanical and a fluidic and an electrical connection is described in which each can in principle be optimised independently from the others.
Consequently, there is a demand for a technology for building hybrid microfluidic systems from a set of more or less standard components that is as generic as possible and that can be automated in a large measure. The process and the materials should be as freely selectable as possible for each type of connection: fluidic, electrical and mechanical. The purpose of the present invention is to meet this demand.